I'm still waiting for a game where the big bad just says "Fuck your rules" and fights you for real.
I meant more along the lines of characters actually using their unique ability to kill. Like Suika making the air density around the character increase, crushing them to a bloody pulp. Or Yukari gapping their internal organs out of their body. Or Flandre going 'kyu'
Assuming I'm reading it right (there's a 3% margin of error for misinterpretation), spell card rules are written as a devil's contract. A devil's contract is unbreakable. Which means super powered characters like Suika, Yukari, or Flandre couldn't break them even if they wanted to (well, maybe Yukari could. MAYBE. I suppose she could do something like destroy the boundary between legit contract and illegit contract if she really felt like it. Not that I know why she'd ever want to because there's rudimentary evidence that she's the one that wrote the rules in the first place)
Sources: Foot note #2 here states devil contracts are unbreakable
http://touhou.wikia.com/wiki/Perfect_Memento:_Encyclopedia:_VampireThe spell card rules are stated to be a devil (vampire) contract here (3% chance of misinterpretation. But it does appear that it's merely a revision to the devil contract already in place that was made after the Vampire incident was finally put down):
http://touhou.wikia.com/wiki/Perfect_Memento:_Reimu_HakureiNote: Apparently just because a devil's contract is unbreakable doesn't mean that characters can't bend the rules a little. ...or a lot in Suika's case (Marisa gets annoyed when analyzing Suika's spell cards in Grimoire of Marisa, complaining that Suika turning huge should be against the rules because it isn't danmaku at all). Course, given that Reimu approves most of the spell cards (somehow. How this process works for characters Reimu never met before like Suika or Byakuren is beyond me), it's possible that Suika simply got Reimu really drunk when she approved that one.
Who indeed? A human drafted the spell card rules. The same humans who regularly defy the "do not attack without reason" clause to virtually no consequence. They're rewarded instead. This is an injustice against youkai. A neutral third party is needed to put things right.
Er... actually, Akyu was saying that it appears that a YOUKAI drafted the spell card rules. The original draft of the spellcard rules was written on the same type of paper as the youkai contract, which is something a youkai would write on. Akyu then went on to basically ask who the person proposing these rules to the shrine maiden (Reimu) actually was. This is why the draft is located in the "unsolved mysteries" section of Perfect Memento. Because the writer of the original rules is an unsolved mystery.
Off-topic: The original writer is either a character ZUN hasn't introduced to us yet and probably a devil, or Yukari. From Reimu's profile, we know that the writer is female and loves beautiful things, which is why Danmaku was chosen and other methods were rejected. We also know that it's a devil's contract, although I'm sure it's possible for another youkai to use a devil as a liason to make the contract. Logic implies the rules were written up by a youkai considered to be a leader amongst Youkai. Yukari pretty much fits all these traits besides the vampire thing, as Perfect Memento states in Yukari's profile that she always is wearing extravagant clothes (loves beauty) and Yukari being a leader of Youkai is all over the place. We also know that Yukari tries to balance out her own power to account for weaker foes just like the spell card system does in a way (from Yukari's Perfect Memento profile), so she'd be the type to come up with this sort of thing.
http://touhou.wikia.com/wiki/Perfect_Memento:_Reimu_HakureiIf the spell card rules were written by a vampire, it is 99% chance that it is NOT Remilia who wrote it. The spell card rules were written by someone who chose danmaku because they were preferred among women and youkai, but Remilia has been shown on several occassions that she prefers brute force, not Danmaku (ZUN's comments about her last word card in Imperishable Night, and she opts to switch to brute force against the Watsuki sister in Silent Sinner in Blue)
Oh, and if the spell card drafter really was Yukari, she probably just teleported the memo to Reimu without actually meeting her face-to-face, since Perfect Cherry Blossom was apparently the first time Reimu saw Yukari in person, judging by the dialogue (but not the first time Yukari saw Reimu)